This invention relates to high frequency Gunn effect oscillators.
As shown by Gunn in U.S. Pat. No. 3,365,583, f, the primary mode oscillating frequency of a Gunn effect diode is given by f=v/L, where v is the drift velocity of the electrons and L is the length of the diode in the direction of current flow. Thus, the physical length of the diode limits the oscillating frequency of a conventional Gunn-effect oscillator.
There is a long standing desire to improve the operating characteristics of Gunn-effect oscillators. One area of study has been to increase the oscillating frequency; the primary method for increasing the oscillating frequency is reducing the diode length. However, below some minimum length further reductions are ineffective because sufficient length is required for the Gunn instability to act, i.e., for carrier heating and inter-valley transfer to occur. Conventional Gunn-effect diodes of doped Gallium Arsenide can be made to oscillate at frequencies up to 100 GHz. Improvement has also been sought in the signal power available from an oscillator.